server_request.cpp

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>
#include "format.cpp"

static int on = 1, off = 0;
static const int MAX_BUF = 4096;

int one_request(int c_fd){
        int len = parse_len(c_fd);
        if(len<0){
                return -1;
        }
        assert(len<MAX_BUF);
        
        char rbuf[MAX_BUF] = {};
        int n = read_all(c_fd,rbuf, len);
        if(n<0){
                return -1;
        }

        printf("Client says: %s\n",rbuf);

        char wbuf[4+MAX_BUF]={};
        char msg[] = "Hello, from the server";
        int sz = strlen(msg);
        memcpy(wbuf+4,msg,sz);
        write_len(sz, wbuf);
        
        n = write_all(c_fd,wbuf,sz+4);
        if(n<0){
                return -1;
        }

        return 0;
}

int main(){
        int fd = socket(AF_INET,SOCK_STREAM,0);
        setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on));

        struct sockaddr_in addr = {};
        addr.sin_family = AF_INET;
        addr.sin_port = htons(1234);
        addr.sin_addr.s_addr = htonl(0);
        int n = bind(fd,(const struct sockaddr*)&addr,sizeof(addr));
        if(n){
                perror("Couldn't bind the socket\n");
        }

        n = listen(fd,10);
        if(n){
                perror("Couldn't listen on the socket\n");
        }
        printf("Server is listenting!!!\n");

        while(true){
                struct sockaddr_in c_addr = {};
                socklen_t len = sizeof(c_addr);
                int c_fd = accept(fd,(struct sockaddr*)&c_addr,&len);
                if(c_fd<0){
                        perror("Couldn't connect to the client\n");
                        continue;
                }

                while(true){
                        int err = one_request(c_fd);
                        if(err){
                                break;
                        }
                }
                printf("Connection closed\n");
                close(c_fd);
        }
}